Just looking at the historical release schedule, if it was installed in 2006, then the installation was a v1.5, a v1.6 or a v1.7 (released in November 2006) they being the active releases during that time period. If you updated a v1.7 to a v1.9.7 with even partial success, then you have done something a lot of people have never been able to do, so congratulations. And you should be experiencing a number of issues - in fact a huge number of issues. So please let us know what versions you are using and what you updated from and to.
Howard is right, to a point, it is better to know what has broken your Moodle to begin with, but there comes a point where you can be wasting too much time on trying to find the issue without result. Best then to do a data dump to a csv file and wipe everything out to start again with a fresh install.
You should always have a localhost copy of your Moodle, for emergencies and for testing. That is why I suggest you start with a fresh install to a localhost, fill it up, make sure it works then dump everything in your production site. Saves time and you have a duplicate that works. There are some things you need to take care of, the things Visnavath refers to, also run the replace.php to make sure your localhost addresses are replaced with your server addresses, but that should do it... In the end you have a test site, on your local machine, and your production site.